* {
    margin: 0;
    padding: 0
}

p {
    padding-bottom: 10px;
}

h1 {

    font-family: Arial, Helvetica, sans-serif;
    font-weight: normal;
    font-size: 42px;
    padding: 35px;
}

main {
    text-align: center;

}

.window {
    width: 920px;
    height: 445px;
    overflow: hidden;
    margin: 20px auto;
    box-shadow: 0px 0px 3px 0px rgba(0,0,0,0.55);
    position: relative;
    border-radius: 5px;
}

.slides {
    display: flex;
    height: 400px;
}

.menu {
    box-shadow: 0px 0px 3px 0px rgba(0,0,0,0.15);
    position: absolute;
    bottom: 0;
    width: 920px;
    height: 45px;
    background: #F1F1F1;

}

.menu>ul {
    display: flex;
    list-style: none;
    justify-content: center;
}

ul>li {
    width: 60px;
    height: 45px;
    list-style: none;
    display: inline-block;
    overflow: hidden;
    border: 1px solid #F9F9F9;
    position: relative;
}

ul>li.active {
    background: #AAAAAA;
    border: none;
    outline: none;
}
ul>li.active>a:hover {
    background: #AAAAAA;
}
li>a {
    text-decoration: none;
    display: block;
    padding-top: 10px;
}
li>a:hover{
    background: #EEEEEE;
}
li>div{
    display: none;
}

li >div.show {
    position: absolute;
    left: 23px;
    width: 0;
    height: 0;
    border-width: 7px;
    border-style: solid;
    border-color: #ffffff transparent transparent transparent;
    cursor:default;   /*这个是去掉鼠标移动到a标签上的手，还原成箭头 */
    display: inline-block;
}

.slides {
    transition: all 0.8s;
}

.slides>img {
    width: 100%;

}